Radial/axial bearing

ABSTRACT

The combined radial/axial bearing has an outer running track formed by a radially inward-pointing rim of the cylindrical sleeve, an inner running track formed by a radially outward-pointing rim of an inner ring and the axes of rotation of the cylindrical rolling bodies in the inner running track intersect with the axes of rotation of the cylindrical rolling bodies in the outer running track virtually at a center of the cylindrical rolling bodies in the outer running track.

FIELD OF USE OF THE INVENTION

The invention relates to a radial/axial bearing consisting of a radialbearing received in a cylindrical sleeve and having cylindrical rollingbodies and of an axial bearing having cylindrical rolling bodies, saidradial bearing and said axial bearing being connected to form a captivestructural unit.

BACKGROUND OF THE INVENTION

A combined radial/axial bearing designed generically in this way ispreviously known from DE-A-20 47 421. The mounting, illustrated in FIG.2, for the absorption of radial and axial forces consists of a radialneedle bearing which is received in a cylindrical sleeve and the rollingbodies of which are held and guided in a cage. Inserted into thecylindrical sleeve on the right side is a first running disk serving asa running track for an axial rolling bearing, the bearing needles ofwhich are guided, in turn, in a cage. The axial bearing includes afurther running disk which is connected to the first running disk byflanging. A complete captive structural unit consisting of a radial andan axial bearing is thereby formed.

The disadvantage of this is that, in such a bearing arrangementaccording to the previous prior art, the arrangement of the radial andthe axial bearing in relation to one another necessitates a large radialconstruction space which is not always available in specificinstallation situations. The further disadvantage is that such agenerically designed bearing is composed of three structural parts ofrelatively complicated form which have to be connected to one another ina complex way in order to form a captive bearing structural unit.

Another generically designed radial/axial bearing has become known fromDE 68 08 805 U. Its outer ring for the needles of the radial bearingaccording to FIG. 1 which are guided in a cage is provided at one endwith a radially inward-directed rim and at the other end merges into aradially outward-running flange which serves as a running disk for theneedles of the axial bearing which are guided in the cage and at its endhas an axially directed collar. The loose running disk is equipped inthe bore with an axially directed collar, on which are provided aplurality of indentations distributed uniformly over the circumference.These indentations engage behind the shoulder of a sheet-metal ringwhich is inserted into the outer ring and which has at the other end aradially inward-directed rim. The cage is guided axially by means of thetwo rims, and the loose running disk is held by means of the shoulder,so that the bearing forms a closed structural unit.

The disadvantages mentioned above also apply to this bearingarrangement, that is to say this radial/axial bearing likewise needs alarge radial construction space.

SUMMARY OF THE INVENTION

Proceeding from the disadvantages of the previous prior art, therefore,the object on which the invention is based is to provide a compactrolling mounting with a radial roller bearing and with an axial rollerbearing, in which rolling mounting a maximum load-bearing capacity isachieved in the radial and in the axial direction, while a predeterminedconstruction space is utilized as favorably as possible.

According to the invention, this object is achieved, in that an outerrunning track of the axial bearing is formed by a radiallyinward-pointing rim of the cylindrical sleeve, said rim adjoining anaxially outward-projecting cylindrical portion of the sleeve, while aninner running track of the axial bearing is formed by a radiallyoutward-pointing rim of an inner ring of the radial bearing or by arunning disk, prolongations of axes of rotation of the cylindricalrolling bodies of the radial bearing intersecting with axes of rotationof the cylindrical rolling bodies of the axial bearing at a center ofthe cylindrical rolling bodies of the axial bearing.

The decisive advantage of the bearing arrangement designed according tothe invention is that the simultaneous absorption of radial and axialloads does not have to be at the expense of an enlarged radialconstruction space. By virtue of the special arrangement and design ofthe rolling bodies of the radial bearing and of the axial bearing, thecombined bearing structural unit is received by the cylindrical sleeveboth in the axial and in the radial direction, so that radial and axialforces can be absorbed in a confined space.

A further advantage arises in that the entire bearing arrangementconsists of few bearing structural parts which have relatively simplegeometric forms and can thereby be produced cost-effectively. Thisresults, as a further advantage, in a substantially simplified assemblyof the entire arrangement, which further lowers the production costs ofthe bearing structural unit.

Further advantageous design variants of the invention are also obtainedby one or more of the following items.

The rolling bodies of the radial bearing have a smaller ratio ofdiameter to length than the rolling bodies of the axial bearing.

The rolling bodies of the radial bearing are designed as needles with aratio of diameter to length of 1:2.5 to 1:10.

The radially inward-pointing rim of the cylindrical sleeve is providedwith an axially inward-pointing flange. This ensures that the rollingbodies of the axial bearing cannot fall out inwardly in the radialdirection in the absence of a bearing cage.

The rolling bodies of the radial bearing and the rolling bodies of theaxial bearing are guided in each case in a cage.

The cylindrical sleeve and the inner ring to be produced by means of anoncutting shaping operation. The respective components of the overallbearing arrangement can thus be produced cost-effectively.

The invention is explained in more detail by means of the followingexemplary embodiments.

FIG. 1 illustrates a longitudinal view of the radial/axial bearing ofthe present invention;

FIG. 2 illustrates the bearing of FIG. 1 along lines II-II of FIG. 1;

FIG. 3 illustrates a longitudinal view of the radial/axial bearing ofthe present invention having a cage for the radial bearing;

FIG. 4 illustrates the bearing of FIG. 3 along lines IV-IV of FIG. 3;

FIG. 5 illustrates a longitudinal view of the radial/axial bearing ofthe present invention having a cage for both the radial bearing and theaxial bearing;

FIG. 6 illustrates the bearing of FIG. 5 along lines VI-VI of FIG. 5;

FIG. 7 illustrates a longitudinal view of the radial/axial bearing ofthe present invention having cages for both the radial and the axialbearing and having a disk acting as the inner running track of the axialbearing; and

FIG. 8 illustrates the bearing of FIG. 7 along lines VIII-VIII of FIG.7.

DETAILED DESCRIPTION OF THE DRAWINGS

The full-roller radial/axial bearing, illustrated in FIGS. 1 and 2,designated by 1 and rotating about a bearing axis 15, is composed of thecylindrical sleeve 2 and of the inner ring 7 which overlap one anotherin the axial direction and are both produced by means of a noncuttingshaping operation. The bearing arrangement 1 includes, further, theaxially oriented rolling bodies 9, designed as bearing needles, for theabsorption of radial forces and the radially oriented rolling bodies 12for the absorption of axial forces. As can also be seen, the cylindricalsleeve 2 merges at its left end into the radially inward-directed rim 3,while it is continued on the right side by the cylindrical portion 4,the diameter of which is slightly smaller than the diameter of theremaining cylindrical sleeve 2. This cylindrical region 4 merges intothe radially inward-directed rim 5, which is continued, in turn, by theaxially inward-directed flange 6, the inside diameter of the latterbeing slightly larger than the inside diameter of the inner ring 7. Thisensures that, with a cylindrical sleeve pressed in a housing, notillustrated, a shaft received by the inner ring 7 and likewise notillustrated is not in contact with the permanently pressed-in sleeve 2.The inner ring 7 is provided at its end on the right side with theradially outward-directed rim 8, for the rolling bodies 9 of the radialbearing the outer running track 10 being formed by the cylindricalsleeve 2 and the inner running track 11 being formed by the inner ring7. The outer running track 13 of the cylindrical rolling bodies 12 ofthe axial bearing is formed by the rim 5 of the cylindrical sleeve 2,while the inner running track 14 is formed by the rim 8 of the innerring.

As FIG. 1 also shows, the cylindrical rolling bodies 9 of the radialbearing which are designed as bearing needles have a ratio of diameterto length of about 1:4, while the cylindrical rolling bodies 12 of theaxial bearing have a ratio of about 1:0.6. Within the meaning of theinvention, a pellet-shaped design of the cylindrical rolling bodies 12may be referred to in this respect. It can also be seen that the radialextent of the cylindrical rolling bodies 12 of the axial bearing isslightly smaller than the radial extent of the rolling bodies 9 of theradial bearing, that is to say is slightly smaller than their diameter.The radial extent of the cylindrical rolling bodies 12 of the radialbearing is in this case governed by the diameter of the cylindricalrolling bodies 9 of the radial bearing. The larger their diameter is,the thicker the rolling bodies 12 may also be, as seen in the directionof their axis of rotation 17. The prolongations of the horizontallyrunning axes of rotation 16 of the cylindrical rolling bodies 9 of theradial bearing intersect the vertically running axes of rotation 17 ofthe cylindrical rolling bodies 12 of the axial bearing at the center orvirtually at the center of the rolling bodies 12. This ensures that, onthe one hand, no additional radial construction space is required and,on the other hand, relatively high axial loads can be transmitted.Cylindrical rolling bodies 12 with a large ratio of diameter to axiallength make it possible for the combined bearing to absorb the axialloads in a construction space which is virtually the same size as theradial bearing itself. Moreover, it is advantageous to use rollers 12 inpellet form for the absorption of axial loads, because their increase indiameter has a greater effect on the dynamic load-bearing capacity thantheir longitudinal extent.

The radial/axial bearing 18 illustrated in FIGS. 3 and 4 differs fromthe bearing 1 shown in FIGS. 1 and 2 merely in that the cylindricalrolling bodies 9 of the radial bearing are guided in a cage 19.

The radial/axial bearing 20 shown in FIGS. 5 and 6 has, as compared withthe bearing 18 shown in FIGS. 3 and 4, an additional cage 21 in whichthe cylindrical rolling bodies 12 of the axial bearing are held. In thisembodiment, the flange 6 of the cylindrical sleeve 2 may be dispensedwith.

Finally, FIGS. 7 and 8 show a radial/axial bearing 22, in which theinner running track 14 of the cylindrical rolling bodies 12 of the axialbearing is formed by the running disk 23.

REFERENCE SYMBOLS

-   1 Radial/axial bearing-   2 Cylindrical sleeve-   3 Rim-   4 Cylindrical portion-   5 Rim-   6 Flange-   7 Inner ring-   8 Rim-   9 Cylindrical rolling body-   10 Outer running track-   11 Inner running track-   12 Cylindrical rolling body-   13 Outer running track-   14 Inner running track-   15 Bearing axis-   16 Axis of rotation-   17 Axis of rotation-   18 Radial/axial bearing-   19 Cage-   20 Radial/axial bearing-   21 Cage-   22 Radial/axial bearing-   23 Running disk

1. A radial/axial bearing comprising: a radial bearing received in acylindrical sleeve, having cylindrical rolling bodies positioned betweenthe cylindrical sleeve and an inner ring; and an axial bearing havingcylindrical rolling bodies, said radial bearing and said axial bearingbeing connected to form a captive structural unit and arranged axiallyone beside the other substantially in one plane, wherein an outerrunning track of the axial bearing formed by a first radiallyinward-pointing rim at one end of the cylindrical sleeve, said first rimadjoining an axially outward-projecting cylindrical portion of thesleeve, which is smaller than the diameter of the cylindrical sleeve; aninner running track of the axial bearing formed by a radiallyoutward-pointing rim of the inner ring of the radial bearing, such thatthe axes of rotation of the cylindrical rolling bodies of the radialbearing intersects the axes of rotation of the cylindrical rollingbodies of the axial bearing at a center of the cylindrical rollingbodies of the axial bearing; a second radially inward pointing rim atthe other end of the cylindrical sleeve, such that said cylindricalsleeve with said first rim and said second rim form the outside of thecaptive structural unit.
 2. The radial/axial bearing as claimed in claim1, wherein the rolling bodies of the radial bearing have a smaller ratioof diameter to length than the rolling bodies of the axial bearing. 3.The radial/axial bearing as claimed in claim 1, wherein the rollingbodies of the radial bearing are designed as needles with a ratio ofdiameter to length of 1:2.5 to 1:10.
 4. The radial/axial bearing asclaimed in claim 1, wherein the first radially inward-pointing rim ofthe cylindrical sleeve is provided with an axially inward-pointingflange.
 5. The radial/axial bearing as claimed in claim 4, whereindiameter of the axially inward-pointing flange is larger than the insidediameter of the inner ring.
 6. The radial/axial bearing as claimed inclaim 1, wherein the rolling bodies of the radial bearing are guided ina cage.
 7. The radial/axial bearing as claimed in claim 1, wherein therolling bodies of the axial bearing are guided in a cage.
 8. Theradial/axial bearing as claimed in claim 1, wherein the cylindricalsleeve and the inner ring are produced by means of a noncutting shapingoperation.
 9. The radial/axial bearing as claimed in claim 1, whereinthe radial extent of the cylindrical rolling bodies of the axial bearingis smaller than the radial extent of the cylindrical rolling bodies ofthe radial bearing.